Ethylene copolymer, composition including the copolymer, and shaped article and film or sheet formed from the ethylene copolymer or the composition

Abstract

Objects of the invention are to obtain ethylene copolymers which have excellent rubber elasticity even without being crosslinked and maintain sufficient shaping processability even when filled with significantly large amounts of additives, and to provide methods for producing with good productivity films or sheets having flexibility and high stretchability. The invention is directed to an ethylene copolymer (X) including structural units derived from a component [A], a component [B] and a component [C] which are ethylene [A], an α-olefin of 3 to 20 carbon atoms [B] and a polyene and/or a cyclic olefin [C]. In the ethylene copolymer, (1) the content of structural units derived from the ethylene [A] is in the range of 50 to 90 mol % in 100 mol % of all the structural units in the copolymer (X); (2) the content of structural units derived from at least one polyene and/or the cyclic olefin [C] is in the range of 1.0 to 5.0 mol % in 100 mol % of all the structural units in the copolymer (X); and (3) the intrinsic viscosity [η] of the ethylene copolymer (X) as measured at 135° C. in a decalin solution is in the range of 7.8 to 13.0 dl/g. The invention also concerns with a composition including the ethylene copolymer (X), and uses.

The invention claimed is: 
     
       1. An ethylene copolymer (X) , which satisfies the following (i) and (ii), comprising structural units derived from a component [A], a component [B] and a component [C] which are ethylene [A], an α-olefin of 3 to 20 carbon atoms [B] and a polyene and/or a cyclic olefin [C],
 (1) the content of structural units derived from the ethylene [A] being in the range of 50 to 90 mol% in 100 mol% of all the structural units in the copolymer (X); 
 (2) the content of structural units derived from the polyene and/or the cyclic olefin [C]being in the range of 1.0 to 5.0 mol% in 100 mol% of all the structural units in the copolymer (X); 
 (3) the intrinsic viscosity [η] of the ethylene copolymer (X) as measured at 135° C. in a decalin solution being in the range of 7.8 to 13.0 dl/g, 
 (i) the value B obtained from a  13 C-NMR spectrum based on the following equation is 0.9 to 1.0:
   Value  B=[P   OE ]/(2 ·[P   E   ]·[P   O ]) 
 
 (in the equation, [P E ] is the molar fraction of the content of the units derived from ethylene (a) in the random copolymer, [P O ] is the molar fraction of the content of the units derived from the α-olefin (b) in the random copolymer, and [P OE ] is the proportion of the number of α-olefin ethylene chains relative to the number of all the dyad chains in the random copolymer); and 
 (ii) the loss tangent value, tan δ, as determined by dynamic viscoelasticity measurement at −10° C. and 1 Hz is not more than 0.1. 
 
     
     
       2. The ethylene copolymer according to  claim 1 , wherein the component [C] is at least one or more components selected from polyenes. 
     
     
       3. The ethylene copolymer according to  claim 1 , wherein the ethylene copolymer (X) has an intrinsic viscosity [η] in the range of 8.0 to 13.0 dl/g as measured at 135° C. in a decalin solution. 
     
     
       4. The ethylene copolymer according to  claim 1 , wherein the component [C] is 5-ethylidene-2-norbornene (ENB). 
     
     
       5. The ethylene copolymer according to  claim 1 , wherein the component [B] is propylene or 1-butene. 
     
     
       6. An ethylene copolymer composition comprising 100 parts by mass of the ethylene copolymer (X) according to  claims 1 , and 100 to 1000 parts by mass of a plasticizer (Y). 
     
     
       7. The ethylene copolymer composition according to  claim 6 , wherein the ethylene copolymer composition has a loss tangent (tan δ) at 190° C. and 0.01 rad/sec of 0.1 to 1.0. 
     
     
       8. A crosslinked product obtained by crosslinking the ethylene copolymer according to  claim 1 . 
     
     
       9. A rubber shaped article comprising the crosslinked product according to  claim 8 . 
     
     
       10. A film or sheet comprising the ethylene copolymer (X) according to  claim 1 . 
     
     
       11. The film or sheet according to  claim 10 , wherein the component [C] is 5-ethylidene-2-norbornene (ENB). 
     
     
       12. The film or sheet according to  claim 10 , comprising 100 to 1000 parts by mass of a plasticizer (Y) with respect to 100 parts by mass of the ethylene copolymer (X). 
     
     
       13. The film or sheet according to  claim 12 , wherein the plasticizer (Y) is a petroleum plasticizer. 
     
     
       14. The film or sheet according to  claim 10 , which has a durometer type A hardness measured by a method specified in JIS K 6253 of 10 to 80. 
     
     
       15. The film or sheet according to  claim 10 , wherein at least part of the ethylene copolymer (X) has been crosslinked by electron beam crosslinking. 
     
     
       16. The film or sheet according to  claim 15 , which has been crosslinked with an electron beam at a dose of 10 to 200 kGy. 
     
     
       17. A method for forming films or sheets comprising forming with a calendaring machine films or sheets comprising the ethylene copolymer (X) according to  claim 1 . 
     
     
       18. The film or sheet according to  claim 10 , which is a calendered article obtained by calendering. 
     
     
       19. A crosslinked product obtained by crosslinking the ethylene copolymer composition according to  claim 6 .